[NNTP] LIST EXTENSIONS (again)

[Russ Allbery]

Mark Crispin <MRC at CAC.Washington.EDU> writes:

> The effect is to break tens (hundreds?) of thousands of deployed Pine
> clients (and other clients based upon the c-client library), and some
> unknown number of Diablo servers.

> My impression is that most inn servers will *not* be broken if we choose:

>  	STARTTLS
>  	AUTHINFO
>  	MODE READER

> Indeed, even though many people use inn servers with Pine, *nobody* has
> complained about Pine having this order.

> How many inn servers would be broken?  Just a handful?  Wouldn't it be
> easier to fix those handful of inn servers?

Every server that actually requires MODE READER will be broken by that
order.  Fixing the servers that require that order is equivalent to
eliminating MODE READER entirely.

You can see why by observing what MODE READER does on a system that
actually needs it:  it causes a separate program to be spawned and the
connection passed to that program, destroying all established session
state.  There's no way to preserve a TLS connection and an authentication
session across that sort of change.

I'm really sorry that it looked like this was the right thing to do.  :/
This is absolutely the fault of the NNTP community for never having
written a proper specification for MODE READER.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>